1. Field
This invention concerns a unique mounting device for eddy current or capacitive probes or the like which are typically used to detect and measure deviations in shaft balance, misalignment, rotor rubs, vibration or the like of rotating shafts, and finds particular use for mounting a proximity probe accurately on the face of a sleeve bearing housing whereby high visibility is afforded by way of the geometric configuration and other features of the device for aiding the mounting procedure.
2. Prior Art
Proximity (Eddy Current or Capacitive) probes typically are installed either internally, i.e., to the bearing housing (see FIG. 18) or externally (see FIG. 19). Referring to prior art FIG. 18, proximity probe body is typically ⅜-24 thread (English) and is screwed into the probe mounting blocks. Two probes are typically installed at each bearing 90 degrees apart. The probe mounting blocks may be fabricated of steel, aluminum or non-conductive material. The blocks are attached to the end of the bearing with small screws. The probe wire is tied using safety wire ties to prevent damage from the spinning shaft. Among the disadvantages of this type of mounting are that the installation requires an extensive shutdown of the machine, and once installed, the probes are not easily accessed for adjustment or replacement since the machine must again undergo an extensive shutdown involving adequate cooling of the machine and then proper removal of the bearing housings before the probes can be accessed.
Referring to prior art FIG. 19, the probes are screwed into a threaded holder which is then screwed into a probe holder or housing. This probe housing typically has 1″ National Pipe Thread and is screwed into a tapped hole in the bearing housing. Disadvantages of this type of mounting include (a) as with the internal mounting described above, installation requires an extensive shutdown of the machine in order to accurately machine the bearing housings for probe use, and (b) a mechanic or technician climbing on the machine may use the probe housings for a hand hold or may step on the probes causing distortion or damage to the probe housing or holder. Also, the probes could then, after the repairs are made, be screwed closer to or further from the shaft than required giving a false reading in the shaft position within the bearing. Further, if the probe housing were loosened then the probe itself may be loose and the readings would not be stable or accurate.
Applicants principal objective is to provide a probe mounting device that permits temporary, releasable mounting of proximity probes (also called Eddy Current probes or Capacitive Probes) to a standard sleeve bearing housing such as a Dodge Sleevoil type. The present temporary mounting of proximity probes is particularly useful when diagnosing shaft deviation such as vibration of the shaft relative to the bearing housing of fluid film bearings which bearings generate a hydrodynamic oil wedge which supports the shaft or journal. The journal can be thought of as floating on the oil wedge similar to a ship floating on water.
Detailed information on Capacitive Proximity Probes can be found in the following articles.